Addis Ababa: Ethiopian rebels fighting for independence for a region with potentially significant oil and gas reserves said on Saturday they had captured seven towns near the border with neighbouring Somalia.

The Ogaden National Liberation Front (ONLF) wants autonomy for the Ogaden region, whose population is ethnic Somali. The area is drawing interest from foreign oil and gas companies who think its deserts might be rich in mineral deposits.

"The operation ... to capture Obolka, Hamaro, Higlaaley, Yucub, Galadiid, Boodhaano and Gunogabo involved thousands of ONLF troops and resulted in two days of heavy fighting," the rebels said in a statement.

"A significant number of Ethiopian troops have been killed and their military hardware captured or destroyed."

Ethiopian government officials were unavailable for comment, but they routinely deny ONLF statements and say the rebels have been defeated.

Addis Ababa says the ONLF are "terrorists" supported by regional rival Eritrea. The ONLF accuses the Ethiopian military of killing and raping civilians and burning villages in the region as part of its effort to root out insurgents.

The regular accusations from both sides are impossible to verify. Journalists and aid groups cannot move freely in the area without government escorts.

The ONLF statement said its fighters had been "warmly welcomed" by residents in the seven towns and were giving treatment to civilians hurt in the fighting.

The Ogaden region is said to contain mineral deposits and international firms including Brazil`s Petronas and Sweden`s Lundin are exploring its deserts for oil. The ONLF regularly warns foreign companies against prospecting.

Ethiopian forces launched an assault against the rebels -- who have been fighting for more than 20 years -- after a 2007 attack on an oil exploration field owned by a subsidiary of Sinopec, China`s biggest refiner and petrochemicals producer.

The separatist cause has gained momentum due to a low level of development. Until Chinese engineers arrived in the remote region in 2007, the entire area had only 30 km (20 miles) of tarmac road in an area of about 200,000 sq km.